City Nature Clock

How do you know when spring has begun? You could look at a calendar, but everyone seems to have their own definition of when the seasons change: the sugarhouses are making syrup, the first person is seen in shorts, baseball games are on the radio. Nature has its own markers of the seasons, and over the course of Spring 2021, Burlington Wildways, with the help of iNaturalist.org users, set out to track the arrivals and emergence of some of the most common species in Burlington and Winooski, VT. Below you will find clocks that highlight five categories of species: Birds, Wildflowers, Trees, Reptiles & Amphibians, and Insects.

What a spring it was from the spring (vernal) equinox on March 20th to the summer solstice on June 20th, we saw hot days in April and chilly mornings in June, not to mention an uncountabe amount of gypsy moth caterpillars. 56 of the 60 species we set out to track were spotted in our community, and their arrival (and sometimes departure) times are detailed below. To see the photos and sounds recorded, visit the City Nature Clock project on iNaturalist. This project was an expansion on last year's 2020 Burlington Seasons Clock project.

Find other activities to get involved in that are part of the City Nature Celeberation on that webpage, or play Wildways Bingo!

Henry David Thoreau marked the dates of blooming wildflowers, the arrivals of migratory birds, and the occurrence of other animals in his time at Walden Pond and Concord, MA. Researchers today are recording some of the same phenophases and using them to track climate change. A warmer climate has changed average animal and plant behavior by days or even months.

What is a phenophase? The scientific term for nature’s calendar is Phenology. A subset of ecology, phenology is defined as the study of the timing of recurring biological events and how these events are influenced by seasonal variations in climate and other ecological factors. A phenophase is an observable stage in the annual life cycle of a plant or animal that has starting and end points. Plants are the most common focus of phenological studies because of their fixed location and suitability for repeated seasonal observation. Timing of budbreak, leafing, flowering, fruiting, and leaf coloring are the commonly observed phenophases. The timing of bird migration, the dates of salamander courtship, and mammalian hibernation cycles are examples from the animal world.

Results of the City Nature Clock Spring 2021 (Burlington & Winooski, VT)

Birds (20) - Returning with spring!